1. Field of the Invention
The invention is generally directed to packaged electrical circuit components, such as very large scale integrated circuit (VLSI) chips, situated in a high density interconnect (HDI) structure. More particularly, the invention relates to an electrical circuit module that is repairable or reconstructible.
2. Background Information
HDI structures of the type mentioned above are shown and described in U.S. Pat. No. 4,783,695, "Multichip Integrated Circuit Packaging Configuration and Method," issued Nov. 8, 1988, and in U.S. Pat. No. 4,918,811, "Multichip Integrated Circuit Packaging Method," issued Apr. 24, 1990, both assigned to the the assignee of the present invention and herein incorporated by reference.
Manufacturing yield is a significant problem affecting production of electrical circuit modules, including those incorporating HDI structures. To improve yield, a method has been devised for removing and replacing the entire electrical interconnection structure overlying the electrical circuit components, as disclosed in U.S. Pat. No. 4,884,122, "Method and Configuration for Testing Electrical Circuits and Integrated Circuit Chips Using a Removable Overlay Layer," filed Aug. 5, 1988, assigned to the assignee of the present invention, and herein incorporated by reference.
A typical HDI structure comprises a plurality of multiple ply sequences successively stacked over the electrical circuit components and substrate, each sequence including at least a metal layer for electrical connections and an underlying dielectric polymer film for electrical insulation. Thus, refabrication of the entire electrical interconnection structure, which comprises a substantial portion of the module, may be time consuming, wasteful and expensive, particularly where a fault in the module or an engineering design change may affect only one multiple ply sequence or even one ply in the sequence.
The latter patent also discloses a method for removing the outer multiple ply sequence from an HDI structure with two multiple ply sequences. The choice of materials suitable to meet the requirements for such a module, however, is extremely limited. Furthermore, fabricating an electrical circuit HDI module of this type with more than two multiple ply sequences is extremely difficult. Thus, fabricating an electrical circuit HDI module that meets a multiplicity of engineering design and materials requirements and includes the desired capability for reconstruction and repair is not always feasible or practical.
A need exists for a reconstructible electrical circuit HDI module made from commonly available materials to improve the capability to produce defect free modules and to expand the scope of engineering and design alternatives for fabricating such a module.